JPH11205850A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a call termination notice from being mis-tansmitted from a master device owing to the interrupt of a radio wave by transmitting call termination notice sound from a slave device, when a call with the master device terminates. SOLUTION: When the call of a slave device A terminates, the slave device A stops the transmission of a call signal and automatically transmits call termination notice sound and goes into a standby state. A master device 0 detects the absence of a 'BUSY' signal, repeats call termination notice sound from the slave device to respective slave device B-N, stops transmission and goes into the standby state. The respective slave devices B-N receive call termination notice sound. When they recognize it, they make the call and start transmission. Thus, the master device is prevented from mis-judging the termination of the call and transmitting call termination notice sound, even if the radio wave is interrupted at the communication critical point of the slave devices and the master device. Then, notice sound is prevented from being emitted at random owing to mis-judgment and accompanied crosstalk can be prevented and response time improves.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a radio communication system.

[0002]

2. Description of the Related Art In a conventional wireless communication system, in a system call between a plurality of communication devices (child devices) via a relay device (master device), when a certain child device finishes transmitting, the master device The transmission end notification sound of the slave unit is automatically transmitted to inform the slave units other than the slave unit that the transmission has ended.

FIG. 7 is an operation timing chart in the above conventional radio communication system. In the timing waveform in FIG. 7, a low level indicates a standby state, and a high level indicates an operating state (during transmission or relaying). The notification sound is transmitted from the master unit O at the moments of the respective transmission end points A to E by the slave unit A and the slave units B to N. From the master unit O to the slave unit B
Arrows (time points A, C, E) directed to .about.N notify the slave units B to N of the end of the transmission of the slave unit A, and the opposite arrows (time points B, D) indicate any of the slave units B to N. End of transmission
And the other party to be transmitted.

[0004] FIG. 8 is a simplified operation diagram of the conventional radio communication system at the time of transmitting a call end notification sound. 8 shows, for example, the operation at the time point A in FIG. 7, in which the transmission signal of the slave unit A is relayed by the master unit O and each slave unit B
To N. When the transmission of the slave A is completed, the master O
Detects the end of the transmission and transmits a call end notification sound, and each of the slave units B to N receives the transmitted notification sound and confirms the end of the transmission of the slave unit A.

FIG. 9 is a flowchart showing the operation of the above system call. In FIG. 9, slave unit A is in a standby state first, then makes a call, and then sends ATIS after confirming carrier sense. (Here, "carrier sense" is one of the control devices of a specific low-power radio station. In order to prevent interference when receiving a radio wave of a selected channel requested before transmission, it prevents interference. belongs to.
“ATIS” is one of the control devices of a specific low power radio station, and is an individual call name of each radio station, which is transmitted each time transmission is started. Then, the slave A stops transmitting.

[0006] On the other hand, master unit O is in a standby state first, receives ATIS from slave unit A, detects that there is a call from slave unit A, and then confirms carrier sense and then returns to A.
The TIS is sent to each of the slave units A to N to start transmission. Next, each of the slaves A to N detects a BUSY signal (a reception signal sensed by the wireless station) from the master O, and then the slave A starts transmission, the master O starts relay, Each of the slave units B to N starts receiving. Thereafter, a call is made between the slave unit A and the slave units B to N.

At the end of the call of the slave unit A, if the slave unit A stops transmitting and enters the standby state, the master unit O detects the absence of the BUSY signal, and issues a tone to notify the end of the talk of the slave unit A to each slave unit. A to N
To stop the transmission and enter a standby state. Slave unit A
After receiving the notification sound and confirming, it enters the standby state again. When each of the slave units B to N receives and confirms the notification sound, it makes a call, and after confirming the carrier sense, sends ATIS to each of the slave units A to N to start transmission. Next, the master unit O receives the ATIS from the slave units B to N, detects a response, starts relaying the transmission signal, and the slave unit A starts receiving. Thereafter, a call is made between the slave units B to N and the slave unit A.

At the end of the call between the slave units B to N, if the transmission is stopped and the unit enters the standby state, the master unit O detects the absence of the BUSY signal, and issues a call end notification sound for the slave units B to N. A to N
And then start the hang-up. (here,
"Hang-up" means that the time during which there is no BUSY is arbitrarily set, and that the repeater determines that it is in the middle of a call between slaves during the set time, and is in the standby state. In the case of the specific low power radio station, if the hang-up is completed and there is no BUSY for more than 2 seconds, for example, it is determined that the call has ended, and the process returns to the standby state. From the standby state, carrier sense and ATIS are required again. )

[0009] The slave unit A can start transmission after receiving the notification sound and confirming it. When the slave unit A starts transmission, the master unit O detects the presence of BUSY, starts relaying, and sets the slave units B to
N starts receiving. Thereafter, a call is made between the slave unit A and the slave units B to N. Hereinafter, communication between the slave units A to N is performed via the master unit O in a similar operation.

[0010]

However, in the above-described conventional wireless communication system, the communication distance between the master unit and the slave unit is almost at the critical point in the exchange of radio waves between the master unit O and the slave unit. In such a case, communication may be interrupted as shown in FIG. In this case, the base unit determines the end of transmission based on the presence or absence of radio waves of the handset,
Unnecessarily sending out the notification sound of the end of transmission every time the communication is interrupted has occurred.

An object of the present invention is to provide a wireless communication system which solves the above-mentioned conventional problems.

[0012]

A wireless communication system according to the present invention is a wireless communication system in which communication between a plurality of slave units is performed by relaying a master unit. The transmission end notification sound of the handset is transmitted from the handset, relayed by the master, and received by each handset.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the radio communication system according to the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing an embodiment of a wireless communication system according to the present invention, and shows a case where the wireless communication system is implemented in a specific low-power wireless station as an example. In FIG. 1, each of the slave units A to N performs wireless communication with each other by relaying a master unit O (repeater). Each of the slave units A to N emits a transmission radio wave having a transmission frequency of 440 MHz during transmission, and receives a radio wave having a reception frequency of 422 MHz during reception. The master unit 0 has a transmission frequency 44 from each of the slave units A to N.
The transmission radio wave having 0 MHz is converted into a transmission frequency of 422 MHz and relayed.

FIG. 2 is a block diagram showing the configuration of the master unit in FIG. In FIG. 2, 1 is a microcomputer (hereinafter referred to as a microcomputer), 2 and 3 are AF (audio frequency) amplifiers, 4 is a VCO (voltage controlled oscillator),
5 is a driver unit, 6 is a power amplifier, 7 is an antenna, 8 is an RF (radio frequency) amplifier, 9 is a VCO (voltage controlled oscillator), 10 is a mixer, 11 is an IF (intermediate frequency) amplifier, 12 Is a detection unit.

FIG. 3 is a block diagram showing a configuration example of each slave unit in FIG. 21 is a microcomputer, 22 is an AF amplifier, 23 is a microphone, 24 is a speaker, 25 is a VCO (voltage controlled oscillator), 26 is a driver, 27 is a power amplifier, 28 is an antenna, and 29 is RF (radio frequency) amplification. , 30 is a mixer unit, 31 is an IF (intermediate frequency) amplifier, and 32 is a detector.

In each of the slave units A to N, at the time of transmission, the audio signal is amplified by the AF amplifying unit via the microphone 23.
It is supplied to CO25. The VCO 25 oscillates a carrier signal having a frequency of, for example, 440 MHz under the control of the microcomputer 21, and the oscillated signal is modulated by the audio signal from the AF amplifier 22, and the driver 26, the power amplifier 27, and the antenna 28
Is transmitted to the base unit 0 as a transmission radio wave having a transmission frequency of 440 MHz. At the time of reception,
Radio wave from another slave unit (frequency 422 MH)
z) is received by the antenna 28 and is listened to via the RF amplifier 29, the mixer 30, the IF amplifier 31, the detector 32, the AF amplifier 22, and the speaker 24.

The master unit O receives a transmission radio wave (frequency 440 MHz) from each of the slave units A to N by an antenna 7, and an RF amplification unit 8, a mixer unit 10, an IF amplification unit 11, and a detection unit 12
The signal is demodulated to an audio signal by the, and is amplified and signal-processed (described later) by the AF amplifiers 3 and 2, and then supplied to the VCO 4. VC
O4 oscillates a carrier signal having a frequency of 422 MHz under the control of the microcomputer 1, and this oscillation signal is modulated by an audio signal from the AF amplifying unit 2 and transmitted via a driver 5, a power amplifying unit 6 and an antenna 7 to a transmission frequency of 422 MHz. And transmitted to each of the slave units B to N.

Further, as a communication mode between the slave units, a group communication mode and a scramble communication mode can be set. The group call mode is a mode in which only the voice of the other party (wireless station) having the same channel and group number can be heard. Also, the scramble call mode is a confidential conversation, and a person who is not in the scramble call mode (radio station)
In this mode, conversation cannot be heard. The AF amplification units 2 and 3 of the master unit O amplify the demodulated audio signal from the detection unit 12 and also have a processing function of performing signal processing suitable for each mode in the group and scramble communication modes under the control of the microcomputer 1. Have.

Therefore, the present invention is characterized in that, in the above-described configuration, the notification sound of the end of transmission is not automatically transmitted by the slave unit which has been transmitting, but by itself, at the end of transmission.

FIG. 4 is an operation timing chart in the wireless communication system according to the present invention. In the timing waveform in FIG. 4, a low level indicates a standby state, and a high level indicates a state during operation (transmitting or relaying).
At the moments of the respective transmission end points A to E by the slave units A and B to N, the notification sound is transmitted from each slave unit directly to the partner slave unit without passing through the master unit O. The arrows (time points A, C, E) from the child device A to the child devices B to N notify the child devices B to N of the end of the transmission of the child device A, and the opposite arrows (time B, D) Slave unit B
In this case, the transmission end of any one of N to N is notified to the transmission partner including the slave unit A.

Next, FIG. 5 is a simplified diagram of the operation at the time of transmitting the call end notification sound in the wireless communication system according to the present invention.
FIG. 5 shows, for example, the operation at the time point A in FIG. 4, in which the transmission signal of the slave unit A is relayed by the master unit O and each slave unit B
To N. When the transmission of the slave A is completed, the slave A
The microcomputer 21 confirms the end of transmission and notifies the end of the call (for example, stored in the internal memory of the microcomputer 21).
Is supplied to the VCO 25, the oscillation signal of the VCO 25 is modulated by the call end notification sound and transmitted from the antenna 7, the base unit O relays the transmission radio wave of the notification sound, and each of the slave units B to N relays the relayed notification. Receiving sound relay radio waves. Each of the cordless handsets B to N sends the received and detected transmission end notification sound to each microcomputer 2.
In step 1, the end of the transmission of the slave A is confirmed.

FIG. 6 is an operation flowchart of a system call in the wireless communication system according to the present invention.
In FIG. 6, slave unit A is in a standby state first, then makes a call, and then checks ATI after confirming carrier sense.
S is transmitted, and then transmission is stopped.

On the other hand, master unit O is in a standby state first, receives ATIS from slave unit A, detects that there is a call from slave unit A, and then confirms carrier sense and then returns to A.
The TIS is sent to each of the slave units A to N to start transmission. Next, each of the slaves A to N detects a BUSY signal (a reception signal sensed by the wireless station) from the master O, and then the slave A starts transmission, the master O starts relay, Each of the slave units B to N starts receiving. Thereafter, a call is made between the slave unit A and the slave units B to N.

When the communication of the slave A is completed, the slave A stops transmitting the call signal and simultaneously transmits a sound indicating the end of the talk, and then enters a standby state. The master unit O detects the absence of the BUSY signal, and then issues a call end notification sound of the slave unit A to each of the slave units B to N.
And then stop transmitting and enter a standby state.
When each of the slave units B to N receives and confirms the relayed notification sound, it makes a call, and then checks ATI after confirming carrier sense.
S is transmitted to each of the slave units A to N to start transmission. Then
Master O receives the ATIS from slaves B to N, detects a response, starts relaying the transmission signal, and slave A starts receiving.
Thereafter, a call is made between the slave units B to N and the slave unit A.

When the communication between the slave units B to N ends, the slave units B to N stop transmitting the call signal and simultaneously transmit a sound indicating the end of transmission, and then enter a standby state. Master unit O detects that there is no BUSY signal, and issues a call end notification sound of slave units B to N to slave unit A.
And then start the hang-up.

The slave A can start the transmission after receiving the notification sound and confirming it. When the slave unit A starts transmission, the master unit O detects the presence of BUSY, starts relaying, and sets the slave units B to
N starts receiving. Thereafter, a call is made between the slave unit A and the slave units B to N. Hereinafter, communication between the slave units A to N is performed via the master unit O in a similar operation.

As described above, the transmission end notification sound of the slave unit is transmitted by the slave unit itself, relayed by the master unit, and sent to the slave unit of the other party, and as shown in FIG. Even if the transmission signal or the transmission end notification sound is not received by the other handset due to the interruption of the radio wave at the communication critical point of the base unit and the base unit, the other handset transmits until the transmission end notification sound is confirmed. Never start. Accordingly, it is possible to prevent the base unit O from erroneously determining that the transmission has ended due to the interruption of the radio wave at the communication critical point between the base unit and the slave unit as in the conventional system, and to prevent the generation of annoying notification sounds due to the erroneous determination. Yes, thereby avoiding interference.

Further, the troublesome system processing of the prior art, in which the master unit senses the end of the transmission of the slave unit and notifies the other slave unit of the end of the transmission, is simplified, and the response time is improved.

[0029]

According to the present invention, it is possible to eliminate an adverse effect caused by interruption of radio waves at a communication critical point between a master unit and a slave unit.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a wireless communication system according to the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a master unit in FIG. 1;

FIG. 3 is a block diagram showing a configuration example of each slave unit in FIG. 1;

FIG. 4 is an operation timing chart in the wireless communication system according to the present invention.

FIG. 5 is a simplified operation diagram when a call end notification sound is transmitted in the wireless communication system according to the present invention.

FIG. 6 is an operation flowchart of a system call in the wireless communication system according to the present invention.

FIG. 7 is an operation timing chart in a conventional wireless communication system.

FIG. 8 is a simplified operation diagram when a call end notification sound is transmitted in a conventional wireless communication system.

FIG. 9 is an operation flowchart of a system call in a conventional wireless communication system.

[Explanation of symbols]

 A slave unit N slave unit O master unit 1 microcomputer 2 AF amplifying unit 3 AF amplifying unit 4 VCO 5 driver unit 6 power amplifying unit 7 antenna 8 RF amplifying unit 9 VCO 10 mixer unit 11 IF amplifying unit 12 detecting unit 21 microcomputer 22 AF Amplifying unit 23 Microphone 24 Speaker 25 VCO 26 Driver unit 27 Power amplifying unit 28 Antenna 29 RF amplifying unit 30 Mixer unit 31 IF amplifying unit 32 Detecting unit

Claims (1)

[Claims] 1. A wireless communication system in which communication between a plurality of slaves is performed by relaying a master, wherein a transmission end notification sound of the slave is transmitted from the slave and relayed by the master. A wireless communication system configured to be received by each slave unit.